[Correlation between fat and iron accumulation in the liver and pancreas of obese patients with glycemic metabolic indicators, and analysis of risk factors for glycemic abnormalities].

Objective: To explore the correlation between fat and iron accumulation in the liver and pancreas of obese patients with glycemic metabolic indicators, and to analyze the risk factors for glycemic abnormalities in obese patients. Methods: A prospective study enrolled 160 obese patients who visited Xiangya Third Hospital of Central South University from October 2022 to October 2023. The age [M (Q1, Q3)] was 40.8 (29.5, 43.9) years, with 74 males and 86 females. According to the results of the oral glucose tolerance test (OGTT), they were divided into the normal glucose metabolism (NGT) group(n=68), the impaired glucose tolerance (IGR) group(n=37), and the type 2 diabetes mellitus (T2DM) group(n=55). The proton density fat fraction (PDFF) measured by the MRI-based Dixon technique was used to quantitatively assess the fat content in the liver and pancreas, and the R2* value was used to quantify the iron content in the liver and pancreas. Correlation analysis was used to analyze the correlation between fat and iron deposition in the liver and pancreas of obese patients and glucose metabolism indicators. The multivariate logistic regression model was used to analyze the influencing factors of abnormal glucose metabolism in obese patients. Results: The differences in liver PDFF, liver R2*, pancreatic PDFF, and pancreatic R2* among the three groups were all statistically significant (all P<0.05). The pancreatic PDFF in the T2DM group [12.8% (6.9%, 18.5%)] was higher than that in both the NGT group [7.6% (4.7%, 10.3%)] and the IGR group [7.0% (4.1%, 12.0%)] (all P<0.05). The pancreatic R2* in the T2DM group [33.7 (28.3, 39.0)/s] was higher than that in the NGT group [28.6 (26.3, 33.3)/s] and the IGR group [28.5 (25.9, 32.9)/s] (all P<0.05). Significant differences were also observed among the three groups in terms of the homeostatic model assessment of insulin resistance (HOMA-IR), the homeostatic model assessment of β-cell function (HOMA-β), the insulin sensitivity index (ISI), and blood glucose levels at 0, 0.5, and 2.0 h during the oral glucose tolerance test (OGTT) (all P<0.05). The T2DM group had the lowest HOMA-β, while the NGT group had the highest (all P<0.05). Liver PDFF was positively correlated with HOMA-IR and blood glucose levels at 0, 0.5, and 2.0 h during OGTT (all r>0.25) and negatively correlated with ISI (r=-0.54) (all P<0.05). Pancreatic PDFF was negatively correlated with HOMA-β (r=-0.27) and positively correlated with blood glucose levels at 0, 0.5, and 2.0 h during OGTT (all r>0.24) (all P<0.05). Liver R2* was positively correlated with HOMA-IR and blood glucose levels at 0, 0.5, and 2.0 h during OGTT (all r>0.24) and negatively correlated with ISI (r=-0.29) (all P<0.05). Pancreatic R2* was negatively correlated with HOMA-β (r=-0.26) and positively correlated with blood glucose levels at 0, 0.5, and 2.0 h during OGTT (all r>0.21) (all P<0.05). Multivariate logistic regression analysis revealed that liver PDFF≥9.4% (OR=0.044, 95%CI: 1.03-5.76) was a risk factor for abnormal glucose metabolism in obese patients. Conclusions: Fat and iron accumulation in the liver and pancreas of obese patients is closely related to the occurrence of abnormal glucose metabolism. Fat deposition in the liver is a risk factor for abnormal glucose metabolism in obese patients.